Tower supported microwave reflector with adjustable mount



April 22, 1969 J. S. KREITZBERG TOWER SUPPORTED MICROWAVE REFLECTOR WITHADJUSTABLE MOUNT Filed Jan. 24, 1966 l was s.

Sheet of 2 INVENTOR I'I'ZBERG ATTORNEY April 1969 J. 5. KREITZBERG3,440,659

TOWER SUPPORTED MICROWAVE REFLECTOR WITH ADJUSTABLE MOUNT Filed Jan. 24,1966 Sheet 2 of 2 INVENTOR JAMES 3. K ZBERG ATTORNEY United StatesPatent Office 3,440,659 Patented Apr. 22, 1969 US. Cl. 343-882 ClaimsABSTRACT OF THE DISCLOSURE A microwave reflector assembly adapted forinstallation on a rigid support includes an elliptical reflector diskoptionally separable into halves on a mounting frame. The mounting frameis attached to the rigid support and includes a horizontal memberadjacent the horizontal axis, and two pairs of supporting membersconnecting the horizontal member to the rigid support. One pair ofsupporting members extends from one location on the support to oppositeends of the horizontal member while the other pair of supporting membersextends from another location on the support to the opposite ends of thehorizontal member. This provides a gimbal support. Separate adjustingmeans alter the azimuth and elevation relation of the frame to thesupport. Spars are hinged to the mounting frame and there are ribsbetween the face and back skin of the disk. The gimbal mounting supportsthe weight of the reflector assembly without substantial aid from eitheradjusting means.

This invention relates in general to microwave reflectors and, moreparticularly, to microwave reflector assemblies adapted for use inso-called periscope systems.

Microwave systems have become increasingly popular in recent years, notonly with large telephone companies, but also with various otherunrelated industries which have found it convenient as well aseconomical to establish independent communication systems between theirvarious operations situated at different geographical locations.Microwave communication systems, of course, do not utilize land lines toany great extent and can, therefore, traverse impassable terrain.Moreover, they are more economical to maintain and require an initialinvestment which is considerably less in magnitude than conventionalland lines.

In so-called periscope systems, microwaves are generated at ground leveland generally beamed upwardly to a reflector located high above theground where they are intercepted and reflected laterally over theearth's surface to a microwave antenna, relay station, or anotherreflector. In any event the reflector and the device to which it isbeamed must be located a sufiicient height above the ground to avoidinterference from such intermediate objects as buildings, trees, hills,and the like. For this reason, it is desirable to locate the reflectorhigh above the ground, preferably on a tower, with the reflectingsurface located at approximately 45 to the horizontal.

Such reflectors, to operate satisfactorily, must have sub stantiallyflat rigidly mounted reflecting surfaces which will not buckle, bend orotherwise become distorted when subjected to wind and ice loading and toextremes in temperature. Moreover, the reflector must have means forpermitting precise adjustment of the reflecting surface once thereflector assembly is installed on the tower.

The present invention relates to a microwave reflector assembly providedwith a rigidly mounted flat reflecting surface having an ellipticalshape and incorporating means for precisely adjusting the elevation ortilt and azimuth or horizontal angle of such surface.

Among the several objects of the present invention may be noted theprovision of a microwave reflector assembly having a fiat reflectingsurface which will not distort when subjected to wind and ice loadingand to extremes in temperature; the provision of a reflector assembly ofthe type stated having means for providing precise adjustment of thereflecting surface along both vertical and horizontal axes; theprovision of a reflector assembly which is simple and rugged inconstruction and easy to manufacture; the provision of a reflectorassembly of the type stated which can be easily crated and shipped indisassembled condition and thereafter readily assembled at the point ofuse; the

provision of a reflector assembly having a reflector which readily shedssnow and rain water; and the provision of a reflector assembly whichsubstantially eliminates second Fresnel zone effects. Other objects andfeatures will be in part apparent and in part pointed out hereinafter.

The invention accordingly comprises the constructions hereinafterdescribed, the scope of the invention being indicated in the followingclaims.

In the accompanying drawings, in which one of various possibleembodiments of the invention is illustrated,

FIG. 1 is a perspective view of a reflector assembly constructed inaccordance with and embodying the present invention, the reflectorassembly being mounted on a supporting tower;

FIG. 2 is a side elevational view of the reflector assembly;

FIG. 3 is a top plan view of the reflector assembly;

FIG. 4 is a sectional view taken along line 44 of FIG. 2;

FIG. 5 is a segmented elevational view of an adjusting rod forming partof the present invention;

FIG. 6 is a sectional view taken along line 66 of FIG. 1;

FIG. 7 is a sectional view taken along line 77 of FIG. 2;

FIG. 8 is a sectional view taken along line 88 of FIG. 7;

FIG. 9 is a sectional view taken along line 99 of FIG. 6;

FIG. 10 is a sectional view taken along line 1010 of FIG. 9;

FIGS. 11 and 12 are sectional views taken along lines 11-11 and 1212,respectively, of FIG. 6;

FIG. 13 is an enlarged plan view of the rib construction shown in FIG.12;

FIG. 14 is a sectional view taken along line 14-14 of FIG. 6;

FIG. 15 is a sectional view taken along line 1515 of FIG. 14;

FIG. 16 is an elevational view of a reflector mounting tab forming partof the present invention; and

FIG. 17 is a sectional view taken along line 1717 of FIG. 16.

Corresponding reference characters indicate corresponding partsthroughout the several views of the drawings.

Referring now in more detail and by reference characters to thedrawings, which illustrate a preferred embodiment of the presentinvention, 2 designates a microwave reflector assembly which is mountedon an antenna or other suitable tower 4. Tower 4 is conventional indesign and construction and it is, therefore, suflicient for purposes ofthe present disclosure to note that it includes four corner uprights 6,8, 10, 12, which are transversely connected at spaced intervals bycross-members 14. Diagonally connecting cross-members 14 and corneruprights 6, 8, 10, 12, are gusset members 15. Rigidly bolted orotherwise secured to cross-members 14 in slightly outwardly spacedrelation from corner upright 6 and located at a substantial height abovethe ground is vertically extending support pipe 16 which spans severalcrossmembers 14. Support pipe 16 is a standard accessory found onmicrowave antenna towers for mounting antennas thereon. Fastened tosupport pipe 16 by U-bolts or other suitable means are support brackets18, 20, having outwardly projecting horizontally presented tabs 22, 24,provided with axially aligned apertures 26.

Hingedly carried by brackets 18, 20, is reflector assembly 2 including amounting frame 28 provided on its one side with a vertical pipe-likemember 30 having hinge brackets 32, 34, welded or otherwise rigidlysecured to its ends. Hinge brackets 32, 34, include outwardly projectinghorizontal tabs 36, 38, respectively, presented in overlying relation totabs 22, 24, respectively, of support brackets 18, 20, tabs 36, 38,being provided with axially aligned apertures which register withapertures 26 of tabs 22, 24. Fitted through apertures 26, 40, are bolts42, 44, which, in effect, serve as hinge pins for mounting frame 28.Hinge brackets 32, 34, further include wing-like members 46, 48,respectively, each having a downwardly projecting center portion whichmerges into forwardly protruding angulated ears 52. Bolted or otherwisesuitably secured to cars 52 of upper wing-like member 46 are forwardlydiverging upper frame members 54, 56, which converge with forwardlydiverging lower frame members 58, 60, the latter being secured at theirrearwardly presented ends to cars 52 of the lower wing-like member 48.As will be seen by reference to FIG. 4, the forwardly presented ends offrame members 54, 58, and 56, 60, are located in close proximity to oneanother where they are bolted to hinge brackets 62, 64, which are weldedor otherwise secured to the ends of a horizontal cross pipe 65. Brackets62, 64, are identical to brackets 32, 34, and, similarly, includeforwardly projecting tabs 66, 68, respectively, and

wing-like members 70, 72, respectively, the former of which are providedwith axially aligned apertures 74 while each of the latter include anaxially projecting center portion 76 which merges into angulated ears78. Bars 78 of bracket 62 are respectively bolted or otherwise rigidlyfastened to the opposite ends of upper and lower frame members 54, 58,and, similarly, cars 78 of bracket 64 are joined to the opposite ends ofupper and lower frame members 56, 60.

Interconnecting hinge bracket 62 and upright 8 of tower 4 is ahorizontally presented azimuth adjusting rod 82. More particularly,azimuth adjusting rod 82, as will be seen by reference to FIG. 5, isprovided at its ends with pivotal clevis fittings 84, 86, which arebolted respectively to upright 8 of tower 4 and axially projectingcenter portion 76 of wing-like member forming part of hinge bracket 62.Rigidly fastened to clevis fittings 84, 86, are threaded shanks 88, 90,having right and left hand threads respectively. Interposed betweenthreaded shanks 88, 90, is a telescopic sleeve 92 having threadedbushings 94, 96, rigidly fastened in its ends, which bushings engage thethreads of shanks 88, 90. Sleeve 92 comprises a sleeve half 98 whichtelescopically fits within a diametrally larger sleeve half 100 so thatthe effective length of sleeve 92 can be varied. Sleeve half 98 isprovided with a plurality of longitudinally spaced diametrally extendingholes 102 which are adapted to register with diametrally opposedapertures 104 located in the cylindrical wall of sleeve half 100.Adapted for insertion through aligned apertures 104 and a preselectedhole 102 is a lock bolt 106. Thus, sleeve 92 can be extended orshortened until a desired length is reached whereupon apertures 104 arebrought into registration with the nearest hole 102 and lock bolt 106 isfitted therethrough. Further adjustment is obtained by rotating sleeve92 which causes threaded shanks 88, 90, to move inwardly or outwardlyfrom the reversely threaded bushings 94, 96. To facilitate rotation ofsleeve 92, sleeve half 98 is provided in close proximity to bushing 94with radially projecting arms 108 which can be manually grasped androtated. Threadedly mounted on shank 88 intermediate clevis fitting 84and bushing 94 is a lock nut 110 which is run up tightly against bushing94 after the desired azimuth setting is obtained so as to hold thatsetting indefinitely or until another setting is desired. Of course, thehorizontal angle of mounting frame 28 about its axis defined byvertically aligned apertures 26, 40, is dependent on the particularsetting of azimuth adjusting rod 82.

Hingedly mounted on hinge brackets 62, 64, is a reflector 112 includingan elliptical reflect-or disk 114 of monocoque construction andsupporting spars 116, 118, securely fastened to the rear face thereof.Inasmuch as spars 116, 118, are identical in design and constructiononly spar 116 will be described in detail herein. Spar 116 includes aside plate 120 shaped in the configuration of an isosceles triangle andhaving an angle member 122 riveted or otherwise securely fastened alongthe inwardly presented face thereof, angle 122 having a perpendicularlyprojecting flange 124 located in juxtaposition to the bottom margin ofside plate 120. Flange 124 is provided with a plurality of spacedapertures 126. Riveted or otherwise securely fastened to side plate 120along its upper or leg-forming margins are angles 128, 130, andsimilarly along its centerline it is provided with opposed angles 132,134, for lending rigidity thereto. Similarly secured to the oppositeface of side plate 120 and projecting outwardly beyond the apex thereofis a mounting tab 136 provided with an aperture 137. Snugly fittedwithin aperture 137, as best seen in FIGS. 16 and 17, is a self-aligningbearing 138, including an annular outer race 139 which is press-fittedor otherwise tightly inserted in aperture 137. The inwardly presentedface of race 139 is concaved and rotatably accepts an axially protrudingannular inner race 140 having a convexed outer face which is contouredto conform with the contour of the concaved face of outer race 139. Theradii of the complementary concaved and convexed surfaces originate atthe center of bearing 138, thus enabling the inner race 140 to swivelslightly within the outer race 139, as well as to rotate therein.Bearings 138 register with apertures 74 of tabs 66, 68, forming part ofhinge brackets 62, 64. Riveted to angles 132, 134, and transverselyconnecting spars 116, 118, is a spacer member 141 and furtherinterconecting spacer member 141 and angles 132, 134, of spars 116, 118,are diagonally extending braces 142, 144, which lend rigidity to thestructure, all as best seen in FIG. 7. Snugly fitted within apertures 74of tabs 66, 68, and in the juxtaposed self-aligning bearing 138 of spars116, 118, are bolts 146, 148, which in effect form hinge pins whichsupport reflector 112. In other words, bolts 146, 148, form thehorizontal axis about which reflector 112 rotates. Moreover, when bolts146, 148, are drawn up tight, the axially protruding portions of innerrace 140 of self-aligning bearing 138 will be drawn up tightly againstthe outwardly presented faces of tabs 66, 68, but reflector 112 willnevertheless be free to rotate on bearing 138.

Referring now to FIGS. 6 through 15, elliptical reflector disk 114 isprovided with spaced parallel face and back skins 150, 152,respectively, which are preferably formed from relatively narrow gaugesheet steel. Internally disk 114 is provided at spaced intervals with aplurality of transversely extending parallel ribs 154 which maintain theskins 150, 152, in parallel spaced relation to one another. Each of ribs154 has a channel-like crosssectional shape formed by a center portion156 which integrally merges into front and rear flanges 1 58, 160,against which face skin and back skin 152 are held, respectively, bymeans of rivets 162. As will be seen by reference to FIG. 6, ribs 154are of varying length so as to conform to the elliptical shape of disk114. Of course, when manufacturing larger types of reflector disks 114,it may be desirable to fabricate face and back skins 150, 152, from aplurality of transversely extending strips having abutting side marginswhich are presented over flanges 158, 160, of ribs 154. In such aninstance, the number of sheets could conceivably equal the number ofspaces located between ribs 154.

On each side of its longitudinal centerline along lines equally spacedtherefrom and parallel thereto, reflector disk 114 is internallyprovided with a plurality of L- shaped brackets 164 each having a sideflange 166 and a top flange 168 presented perpendicularly to oneanother, as best seen in FIG. 9. Side flange 166 is riveted to centerportion 156 of rib 154 with the outwardly presented surface of topflange 168 presented in underlying abutment with back skin 152. Topflange 168 is provided with a circular aperture 170 located inregistration with a similar aperture 172 formed in back skin 152, bothapertures 170, 172, being in registration with apertures 126 in angles122 forming part of spars 116, 118. Rigidly held to the inwardlypresented face of top flange 168 is a captive nut 174 including anelongated base 176 which is fastened to flange 168 by means ofcountersunk rivets 178. Securely fastened to elongated base 176 inregistration with apertures 170, 172, is an elastic or other suitableself-locking nut 180. Fitted through apertures 126 of spars 116, 118,and apertures 170, 172, are cap screws 182 which engage the threads ofcaptive nut 174 whereby spars 116, 118, are fastened securely toelliptical disk 114 in rearwardly projecting perpendicular relation tothe back skin thereof and in parallel relation to one another.

Referring now to FIG. 11, reflector disk 114 is bisected into diskhalves 184, 186, at transversely extending joints 188, 190, which arepreferably extruded from a suitable metal such as aluminum. Inasmuch asjoints 188, 190, are formed from identical extrusions only joint 188will be described presently in detail. Joint 188 includes detachablejoint elements 192, 194, having mortised locking portions 196, 198,provided with complementary interlocking faces 200, 202, which engageone another and prevent lateral separation of joint elements 192, 194.Complementary interlocking faces 200, 202, are held in facewise abutmentby means of bolts 204 which extend through locking portions 196, 198,and engage captive nuts 206 secured to the inwardly presented face oflocking portion 196. Locking portions 196, 198, laterally terminate atlongitudinal shoulders 208, 210, where they integrally merge intowing-like side portions 212, 214, which are interposed between face skin150 of disk halves 184, 186, respectively, and front flanges 158 of thefirst ribs 154 located on each side of joint 188, flanges 158, face skin150 and side portions 212, 214, being held securely together by rivets216. In this connection, it should be noted that center portions 156 ofthe first ribs 154 are somewhat narrower than center portions 156 of theremaining ribs 154 by a distance equal to the thickness of Wing-likeside portions 212, 214. Moreover, joint elements 192, 194, arepreferably extrusions of identical cross-sectional shape, elements 192,194, being fastened to disk halves 184, 186, in reverse relation to oneanother so that interlocking faces 200, 202, engage one another.

It has already been noted that joint 190 is identical to joint 188.Nevertheless, it is important to note that rear flanges 160 of the firstribs 154 extend over the outwardly presented face of wing-like sideportions 212, 214, thereof where they are held in place along with backskin 152 by means of rivets 216. Moreover, joints 188, 190, are fastenedto disk halves 184, 186, so that complementary interlocking faces 200,202, can be drawn apart when bolts 204 are removed. Thus, reflector disk114 can be readily separated into disk halves 184, 186, for convenienceof crating, shipping and storage. Of course, when reflector 112 is fullyassembled spars 116, 118, lend reinforcement to joints 188, 190, and aidin maintaining true and correct alignment between respective face skins150 of reflector halves 184, 186, by providing a planar face againstwhich back skin 152 and ribs 154 are rigidly supported.

As will be seen by reference to FIGS. 6, 12, and 13, disk half 184 isinternally provided intermediate two of its outer ribs 154 with closelyspaced parallel rib sections 217, 218, each having front and rearflanges 220, 222, which are riveted to face and back skins 150, 152,respectively, and an end flange 224 which is riveted to center portion156 of the outer of the two ribs 154. Rigidly riveted to center portion156 to the same rib 154 intermediate rib sections 217, 218, is anL-shaped bracket 226 having an outer flange 228 located in juxtapositionto the inwardly presented face of back skin 152. Flange 228 is providedwith an aperture 230 and a captive nut 232 rigidly fastened to theinwardly presented face thereof in surrounding relation to aperture 230.Moreover, back skin 152 is provided with an aperture 234 which registerswith aperture 230.

Riveted to face and back skins 150, 152, between two outermost ribs 154of disk halves 184, 186, along the longitudinal centerline of reflectordisk 114 are reinforcing rib sections 236 which are similar to ribsections 217, 218, and similarly projecting beyond end ribs 154 incolineal relation to rib sections 236 are end rib sections 238.

The peripheral edge of reflector disk 114 is sealed by a rim 240 havinga center portion 242 which forms the lateral edge of reflector disk 114,as best seen in FIGS. 14 and 15. Center portion 242 integrally mergesinto inwardly projecting flanges 244, 246, which engage the inwardlypresented surfaces of face skin and back skin 152, respectively. Rim 240is securely held in position by means of angulated connecting members248 which project beyond the ends of ribs 154, connecting members 248having shanks 250 which are riveted to center portions 156 of ribs 154.Shanks 250 integrally merge into flanges 252 which are arcuately bent tomatch the contour of center portion 242 of rim 240 to which they aresecurely fastened preferably by means of rivets. Of course, rim 240 isinterrupted at joints 188, 190, so that disk halves 184, 186, can beseparated.

Interposed between reflector disk 114 and mounting frame 28 is anelevation adjusting rod 254 which is very similar in construction toazimuth adjusting rod 82. It is, therefore, suflicient for the purposesof the present disclosure to note that elevation adjusting rod 254includes a pivotal clevis fitting 256 having a threaded end portion 258which fits through aperture 234 in back skin 152 and aperture 230 inL-shaped bracket 226 beyond which it engages the threads of captive nut232. Clevis fitting 256 is fitted with a threaded shank 260 whichthreadedly engages one end of a telescopic sleeve 262. At its oppositeend, adjusting rod 254 is provided with a pivotal clevis fitting 264which is rigidly bolted to the downwardly projecting center portion 50of wing-like member 48 forming part of bracket 34. Projecting fromclevis fitting 264 is a threaded shank 266 which threadedly engages theopposite end of sleeve 262. Of course, the threads of threaded shanks260, 266, are spiraled opposite to one another so that adjusting rod 254will extend or retract depending on the direction in which sleeve 262 isrotated. Greater extensions or retractions can be obtained by alteringthe telescopic relation between the halves of sleeve 262. Threaded shank266 carries a lock nut 268 which is run up against the end of sleeve 262for holding the same in rigid non-rotatable position with respect toshanks 260, 266. By reference to FIG. 2, it is evident that the angularrelation of reflector disk 114 with respect to the horizontal isdependent on the length or adjustment of elevation adjusting rod 254.

It should be noted that it is desirable to fit clevis fittings 84, 86,256, 264, with self-aligning bearings constructed similar to bearings138 of reflector 112 to prevent binding and yet reduce backlash.

In use, microwave reflector assembly 2 is located on tower 4 immediatelyabove a microwave transmitting and receiving unit (not shown).Transmissions in the nature of microwaves are generated by the unit andbeamed upwardly to reflector 112 which intercepts such microwaves andbeams them laterally over the earths surface toward a distant receivingantenna, relay station, or another reflector. By rotating sleeves 92,262, of adjusting rods 82, 254, respectively, precise elevational andazimuth settings can be imparted to reflector 112 so that it can bebeamed directly at a particular antenna, relay station, or reflector.Inasmuch as adjusting rods 82, 254, support very little, if any, loadthey are extremely easy to manipulate and to do so requires nospecialized tools. In this connection, it should be noted that bolts146, 148, which form the horizontal axis about which reflector 112rotates need not be loosened for the reflector rotates freely aboutselfaligning bearings 138. Furthermore, the azimuth and elevationsettings are independent of one another so that one can be changedwithout disturbing the other. The telescopic construction of sleeves 92,262, of adjusting rods 82, 254, allows a wide range of fine adjustmentwithout utilizing spacers, brackets, and the like. Once a correctsetting is obtained reflector 112 can be rigidly locked in the correctposition merely by tightening lock nuts 110, 268, against sleeves 92,262. When locked in position, reflector 112 will remain rigidly in thatposition making it ideally suited for use with high frequency microwavetransmission systems. The backlash in self-aligning bearings 138 and incle vis fittings 84, 86, 256, 264, is very small and reflectorsmanufactured according to the teachings hereof will move less thanone-tenth degree relative to the tower even under wind and ice loadconditions.

The monocoque constructed of reflector disk 114 provides an extremelyhigh degree of rigidity to the entire reflector 112 in relation to theweight thereof and, more important, maintains face skin 150 in a planarcondition. In this connection, it should be noted that afterinstallation on tower 4 and when not subjected to outside forces, theouter surface of face skin 150 should be perfectly flat, but concavityamounting to no more than Vs inch is permissible. The maximum deflectionof the outer surface of face skin 150 when subjected to wind and iceloading must not be greater than inch toward concavity or convexity.Spars 116, 118, provide a rigid back-up structure for reflector disk 114and further aid in maintaining a perfectly flat or planar reflectorsurface on face skin 150. The design of spars 116, 118, permitsfabrication of such with an accurately controlled straight edge which isbolted to back skin 152 and ribs 154 at closely spaced intervals alongreflector disk 114 by means of cap screws 182. The smooth outer surfaceof back skin 152 has no transversely extending webs or the like whichare susceptible of collecting snow and ice. On the contrary, the smoothback skin 152 readily sheds snow and water and thereby retards icebuild-up which, of course, would create additional forces having atendency to disturb the precise azimuth and clevational settings ofreflector 112. Moreover, whatever ice or snow does build up on disk 114is not against facing skin 150 and continual freezing and thawing cannotthereby distort the reflecting face.

The elliptical shape of disk 114 reduces the weight of the entirereflector 112 and further reduces wind loading by eliminating cornerswhich are not effective as a reflecting surface. Moreover, theelimination of corners presents less area for ice and snow buildup.Furthermore, the elliptical shape provides maximum reflector efficiencyby eliminating second Fresnel zone effects.

The entire microwave reflector assembly 2 can be broken down intoseveral sub-components for convenient crating, transporting and storage.Inasmuch as some of the reflector disks 114 can be as large as 12 feetby 17 feet, this is a decided advantage. Of course, disk 114 isreducible into disk halves 184, 186, and this can be accomplished merelyby withdrawing cap screws 182 and removing spars 1166, 118, from theback of disk 114. After removing bolts 204 complementary interlockingfaces 200, 202, of joints 188, 190, can be separated and disk half 184can be laterally separated from disk half 186. Of course, reflector 112can be readily assembled in the field by reversing the above steps, inwhich case joint elements 188, 190, and spars 116, 118, assure perfectalignment of disk halves 184, 186, and return to the original fabricatedposition. Moreover, bolts 204 hold joint elements 192, 194, rigidly toone another so as to form rigid joints 188, 190, which lend rigidity todeflector disk 114. Furthermore, the interlocking joint elementsdistribute stresses evenly in face and back skins 150, 152, and from onedisk half to the other.

In view of the above, it will be seen that the several objects of theinvention are achieved and other advantageous results attained.

As various changes could be made in the above constructions withoutdeparting from the scope of the invention, it is intended that allmatter contained in the above description or shown in the accompanyingdrawings shall be interpreted as illustrative and not in a limitingsense.

What is claimed is:

1. A microwave reflector assembly adapted for installation on avertically presented rigid support, said assembly comprising a mountingframe on said support, a reflector mounted on said mounting frame andfirst and second adjusting means for altering the angular relation ofthe mounting frame with respect to the vertically presented rigidsupport, the first adjusting means altering the azimuth relation of theframe to the support and the second adjusting means altering theelevation relation of the frame to the support, the mounting framecomprising a horizontal member located adjacent the horizontal axis ofthe reflector and two pairs of supporting members connecting thehorizontal member to the rigid support, one pair of supporting membersextending from one location on said support to opposite ends of saidhorizontal member and the other pair of supporting members extendingfrom another location on said support to opposite ends of saidhorizontal member, the two pairs of supporting members supporting themicrowave reflector assembly without substantial aid from eitheradjusting means.

2. A microwave reflector according to claim 1 in which the firstadjusting means comprises first and second pivotal fittings secured tothe mounting frame and vertical support, respectively, first and secondthreaded shanks rigidly fastened to and projecting from the first andsecond pivotal fittings, the first and second threaded shanks havingopposite threads, a first sleeve interposed between the first and secondshanks, the sleeve having first and second threaded ends which engagethe threads of the first and second threaded shanks, respectively, meansfor changing the length of the sleeve, and means for locking the sleeveto at least one of the threaded shanks, whereby the distance between thepivotal fittings and the angular position of the mounting frame can bechanged by rotating the sleeve.

3. A microwave reflector according to claim 2 in which the secondadjusting means comprises third and fourth pivotal fittings secured tothe reflector and mounting frame, respectively, third and fourththreaded shanks rigidly fastened to and projecting from the third andfourth pivotal fittings, the third and fourth threaded shanks havingopposite threads, a second sleeve interposed between the third andfourth shanks, the second sleeve having third and fourth threaded endswhich engage the threads of the third and fourth threaded shanks,respectively, means for changing the length of the second sleeve, andmeans for locking the second sleeve to at least one of the threadedshanks whereby the distance between the pivotal fittings and the angularposition of the reflector can be changed.

4. A microwave reflector according to claim 3 in which the reflectorcomprises spars hingedly carried by the mounting frame, and anelliptical reflector disk rigidly carried by the spars in outwardlyspaced relation to the mounting frame.

5. A microwave reflector according to claim 4 in which the reflectordisk comprises a back skin, a face skin, and

a plurality of ribs interposed between the face and back skins, theoutwardly presented face of the face skin being planar whereby itreflects microwaves beamed at it, the spars being rigidly secured to theribs.

6. A microwave reflector according to claim 5 in which the ribs arelocated at closely spaced intervals and extend transversely across thereflector disk.

7. A microwave reflector according to claim 5 in which the reflectordisk is optionally separable into first and second disk halves, the backand face skins of the first and second disk halves having abuttingmargins.

8. A microwave reflector according to claim 7 and further characterizedby first and second joint elements rigidly secured to the first andsecond disk halves along the abutting margins thereof, the first andsecond joint elements having opposed interlocking surfaces, and meansfor holding the opposed interlocking surfaces together in interlockingrelation.

9. A microwave reflector according to claim 8 in which the ribs andabutting margins extend transversely across the reflector disk and inwhich the spars are provided with longitudinally extending flat basemembers which are located in perpendicular relation to the ribs, thereflector being further characterized by means associated with the 10spars and ribs for securely holding the reflector disk on the spars withthe back skin in facewise abutment with the base members.

10. A reflector disk according to claim 9 and further characterized by aside rim interposed between the face and back skins and secured to theends of the ribs, the side rim extending peripherally around thereflector disk.

Gabriel Electronics Division, Data Sheet No. 56034, Mar. 22, 1956, 4pp., 343-915.

Tower Construction Co. Catalog, Oct. 1, 1957, pp. 11, 14.

ELI LIEBERMAN, Primary Examiner.

U.S. Cl. X.R. 343-915

